Determination of trimethylamine nitrogen and total volatile basic nitrogen in fresh fish by flow injection analysis
✍ Scribed by Ruiz-Capillas, C; Horner, W?F?A
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 83 KB
- Volume
- 79
- Category
- Article
- ISSN
- 0022-5142
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✦ Synopsis
There are many chemical, microbiological and sensory indices of ®sh quality. Of the chemical indices, TMA-N and TVB-N are probably the most used in connection with remaining shelflife determination. This paper reports on a study of modi®cations to a ¯ow injection analysis (FIA) method necessary to make it suitable for TMA-N and TVB-N determination, speci®cally the optimal concentrations of NaOH and formaldehyde for releasing the volatile bases from the acidic ®sh extract and sequestering the non-TMA volatile bases respectively. The effects of using perchloric acid (PCA) and trichloroacetic acid (TCA) as ®sh extractants were also investigated. The ®sh species used were monk®sh (Lophius piscatorius), skate (Raia clavata) and cod (Gadus morrhua). It was found that 1 M NaOH was the optimal concentration for volatile base release and that 200 g l À1 formaldehyde was adequate for non-TMA base sequestration. Use of PCA and TCA as ®sh extractants appeared to have no signi®cant effect on TMA-N and TVB-N determinations.